omg u guys are just so funny... u are babbeling about things and don't remember anything...
1st. not all Uchicha had the sharingan, only the gifted or "special" ones, who had superior genes - how do u expect them to resurrect Uchicha? simple they rape a lot of women and then one who have the eyes get to be in the ninja army.
2nd. in order to activate Mangekyo Sharingan one needed to have close friend sacrificed/killed, even when Itachi and Sasuke fought - Itachi clearly said u still haven't got the same eyes, then he killed Orochimaru in his seal and BAHH he got them.
3rd. why didnt all have the eyes? not everyone had learned the secret in that tomb or what ever place that was where there was written the secrets, also not everyone had secret intentsions of killing their friends.
4th. ones that read the wall got info (friend must die), some of them did do it. after that happend they read the wall again and saw "ok now i need to kill a buddy with Mangekyo eyes and take them, so i won't go blind if i abuse the powers". -if any of you remember that the further the better the eyes get, the more secrets will be revealed.
5th. Shishui definetly had mangekyo sharingan - how the heck do u expect him to have that genjutsu which controlled people?
6th. if Danzo had the other eye of Shishui, Kakashi becomes Hokage, gets the other eye since the "ROOT" no longer have bad ass DICKtator as their leader and they want new bad ass hokage.
7th. Shishui was good friend of itachi, when he was killed Itachi got Mangekyo Sharingan and saw the terrible truth of Uchicha - which is killing their siblings inorder to advance their own power.
8th. since Madara has such big load of Sharingans I am pretty sure that Eternal Mangekyo isn't the final step, perhaps it has something to do with controlling all the tailed beasts or the fused tailed beast?
anyhow i hope we have good story coming sooner or later and no fillers plez